Over half the world’s population now live in cities. With the United Nations predicting that figure will rise to a whopping 68% in the coming decades.

Existing cities have been constructed in concrete and steel and this has come at a price, and that price is a loss of natural habitats and the wildlife associated with it.

Natural vegetation provides many benefits for the environment from CO2 absorption, reducing the effects of harmful pollutants, cooling, flood prevention the list goes on……problems that they can no longer help with once cleared for a new road or apartment block.

And in constructing and expanding cities we don’t just lose these ecosystem services but we increase the environmental problems by having dense concentrations of polluting transport and industry.

But how do we solve this problem in existing cities and how do we avoid it becoming a problem in new cities that are due to be constructed in the near future?

Well yes we can look to technology to help in some cases, electric cars and better public transport can perhaps help with pollution, but really we need to look back to nature for the solutions. We need to find a way to make our cities greener and full of life once more, and not just human life!

Trees are one of the best natural options we can turn to, they provide large carbon sinks, provide shading and cooling and much more besides. Urban Forestry refers to the practice of incorporating and caring for trees within an urban setting, recognising trees as a vital component of our urban infrastructure.

We can plant trees on street sides, within parks and gardens but there is still the problem of the vast areas of land around them dedicated to concrete that fill our modern cities in the form of high rise buildings. Unfortunately, you can’t plant hundreds of trees on a skyscraper………or can you?

Well I’d seen renderings and pictures of futuristic cities with buildings covered in trees, and I’ll be honest with you I thought they were still the works of fantasy and that in reality this could never happen…..but I’ve been proved wrong because it has been done.

The first vertical forest in the world was designed by Italian architect Stefano Boeri in Milan, completed in 2014. The Bosco Verticale towers are residential apartment blocks…. one of which is over 100m high and most strikingly they are both covered from top to bottom in vegetation. 800 trees, 4,500 shrubs and 15,000 plants make up this urban jungle. The equivalent of 20,000 square metres of forest.

So could this be a way to get more natural vegetation into our cities? Imagine a city covered in these towers forming a network of habitats for wildlife. Well before I get carried away I wanted to speak to Stefano to see how after 5 years since the towers were finished, could they really be a blueprint for future cities? Can they be built affordably? What are they actually like to live in?

Stefano Boeri is quite an amazing person. Born in 1056, in 1972 when Stefan was 16, Friedensreich Hundertwasser an Austrian artist was wandering the streets of his home town Milan with a tree, preaching a new type of architecture based on the presence of plants and trees. At this same time the teenage Stefano was a teenager involved in protesting about social problems such as unemployment and inequality thinking of environmental problems as typical of the capitalist bourgeoisie. He would probably have not have imagined that 35 years later the environment would be at the heart of his architecture.

Stefano has been an architect since the 1980s. Opening his own practice over 10 years ago in Italy and shortly after another practice in Shanghai, China. And now his work focuses on urban visions always with a focus on the geopolitical and environmental implications of urban phenomena.

Stefano is very difficult to get hold of, he is an amazing architect working on many projects, from ongoing projects in existing European cities to constructing brand new green cities in China such as the Nanjing Vertical Forest Project. When I finally tracked him down for a chat, as you will hear, Stefano was on the construction site of an art exhibition in southern Italy where he had transported hundreds of trees that had been destroyed in the vaia storm that devastated northern Italy in October last year to the ancient greek theatre of Syracuse for a performance of Euripide’s tragedy The Trojan Woman.

For this reason you may hear some construction noises going on in the background and I apologise for this but I hope you will enjoy this short chat I had with Stefano and get a feel for the passion he has for trees, vertical forests and urban forestry,